Shamed pop star Justin Bieber has apologised for a second time for using racist language after claims he used the N-word in a video and joked about joining the Ku Klux Klan.

The Canadian heart-throb told The Sun he needed to "take responsibility" for his mistakes and "not let them linger".

He later posted on Instagram a photograph of passages from the Bible, apparently asking for forgiveness.

The 20-year-old singer's latest apology came after the newspaper reported the emergence of a video clip in which he adapts the words to his 2009 hit One Less Lonely Girl to One Less Lonely N****r.

The clip was filmed early in his career after he signed a management deal as a rising child star.

It comes just days after he issued an apology for another poor taste film in which he made a racist joke which he called a "childish and inexcusable mistake".

Speaking to The Sun from Mexico, Justin said that facing up to the mistakes of his past was one of the hardest things he ever had to deal with.

The singer said his actions were totally unacceptable and was worried that his millions of fans might think he was condoning racist behaviour.

"I just hope that the next 14-year-old kid who doesn't understand the power of these words does not make the same mistakes I made years ago," he said, adding: "At the end of the day I just need to step up and own what I did.

"Once again, I am sorry for all those I have let down and offended."

He also took to social media to underline his apology, tweeting a photograph of Bible scripture in an apparent act of seeking forgiveness.

The passage started with the lines: "When your sins weigh heavily upon you, come to Me. Confess your wrongdoing, which I know all about before you say a word. Stay in the Light of My Presence, receiving forgiveness, cleansing, and healing."

It also included Bible passages from the books of John and Isaiah that discuss purification from sin and salvation through God.

Justin has been embroiled in a number of problems in recent months.

Last year he upset young fans by appearing on stage late at a UK gig, meaning many had to leave just moments after he took to the stage and then got into a scuffle with a photographer outside his London hotel.

He is due to stand trial in the US next month on charges of driving under the influence, resisting arrest and driving with an expired licence, after a street race incident in Florida in January.

In April he apologised for posting a picture online from a visit to a shrine in Japan which honoured 14 convicted war criminals.